In a manufacturing process of an array substrate of a thin film transistor display, due to the reasons of signal input, detection precision and cost control, data lines are usually divided into different groups, each group of data lines corresponds to different shorting bars, and each shorting bar is used for transmitting a signal to the corresponding data line group so as to detect each data line. When the data lines are divided into an odd number data line group and an even number data line group, as shown in FIG. 1, the odd number data line group 1 can be directly connected with a first shorting bar L1, and the even number data line group 2 can be connected with a second shorting bar L2 through a via and a connecting piece 3. Wherein the first shorting bar L1 is arranged on the same layer as the data lines, and the second shorting bar L2 is arranged on the same layer as a gate line.
In a process of manufacturing the array substrate by use of a 4-Mask process, for example, during carrying out a channel ashing process, if too many charges are generated on a certain data line in the odd number data line group 1, the overmany charges could be dispersed to other data lines through the first shorting bar L1. At this time, a via and a connecting piece 3 have not been formed between the even number data line group 2 and the second shorting bar L2, thus the data lines in the even number data line group 2 are still separated from each other. If too many charges are accumulated on a certain even number data line, electrostatic breakdown is liable to occur since the overmany charges could not be dispersed, which may cause degradation of the product quality.